1: \(A=\dfrac{3x+\sqrt{x}-3\sqrt{x}-1-3\sqrt{x}+1+8\sqrt{x}}{9x-1}:\dfrac{3\sqrt{x}+1-3\sqrt{x}+3}{3\sqrt{x}+1}\)
\(=\dfrac{3x+3\sqrt{x}}{9x-1}\cdot\dfrac{3\sqrt{x}+1}{3}\)
\(=\dfrac{x+\sqrt{x}}{3\sqrt{x}-1}\)
2: Khi x=1/4 thì \(A=\left(\dfrac{1}{4}+\dfrac{1}{2}\right):\left(3\cdot\dfrac{1}{2}-1\right)=\dfrac{3}{4}:\dfrac{1}{2}=\dfrac{3}{2}\)
3: Để A=6/5 thì \(\dfrac{x+\sqrt{x}}{3\sqrt{x}-1}=\dfrac{6}{5}\)
=>5x+5 căn x=18 căn x-6
=>5x-13 căn x+6=0
=>5x-10 căn x-3 căn x+6=0
=>(căn x-2)(5 căn x-3)=0
=>x=4 hoặc x=9/25
Đúng 4
Bình luận (0)
